The initial response to the incident by company spokesmen and United's CEO, Oscar Munoz, sought to downplay its significance and contrasted starkly with the events depicted in the video, only fueling more outrage among millions fed up with the degrading and humiliating treatment by the major airlines and airport security.
The minister's letter comes after a passenger named David Dao, 69, was dragged off an overbooked United flight in Chicago on Sunday after refusing to leave his seat to accommodate airline crew members.
"Just because you have the right to do something doesn't mean you have the right to do it", says Ronald Mercaldo, Lawyer at Mercaldo Law Firm in Tucson, Arizona. No one should ever be mistreated this way.
It also exposed a corporate culture in which airlines - and United in particular - have long "bullied" passengers, he said.
Demetrio said Dao will "probably" sue over the incident and that the city of Chicago, which employs the guards, is also responsible. On Wednesday, he apologized to Dao, his family and United customers in an ABC News interview, saying the company would no longer use law enforcement officers to remove passengers from overbooked flights. The three other passengers left the plane, but Dao would not.
Officials from United Airlines and the Chicago Aviation Department are being questioned by aldermen about why a man was forcibly removed from a full flight at O'Hare Airport.
David Dao was released from the hospital overnight and was at a "secure location", attorney Thomas Demetrio said at a news conference during which a member of Dao's family spoke out for the first time.
"We were completely horrified and shocked at what had happened to my father", she said.
Demetrio said Dao had told him that being dragged down the plane aisle was more terrifying than his experience fleeing Vietnam in the 1970s.
The security officers returned, but refused to restrain Dao because he was injured and bleeding, Fuller said.
Dao was offered $800 for his seat by United but did not want to take it, Demetrio said.
"He has no interest in ever seeing an airplane", Demetrio said of his client.
Later on Thursday afternoon, United officials reiterated their pledge to fully investigate their procedures to ensure this situation doesn't happen again. Furthermore, they express their belief that the incident was entirely due to the "grossly inappropriate response by the Chicago Department of Aviation", and that all "social media ire" should be directed at them. As a result, all flight crew and cabin crew on Flight 3411 were not United employees, and according to the union, should not be blamed for what happened.
Aviation Commissioner Ginger Evans says the officers had the authority to board the plane but that the rest of what occurred is under investigation.